Radio tuning structure



Jan. 29, 1946. s. s. CRAMER 2,393,591

I RADIO TUNING STRUCTURE v Filed May 23, 1944 2 Sheets-Sheet 1 Z'mnentor 5&2 0am zaww Gttomgg Patented Jan. 29, 1946 UNITED STATES PATENT OF FjlC E RADIO TUNING STRUCTURE Stanley S. C'ramer, Hadd'on fiei glitsyMl;

ApplioationMa-y 23., 1944, Serial No. 536309 This invention relates to a tuning. structure especially adapted for use with a radio: receiving set; and, as: illustrated" in the: drawings; the. tunline structure per Se comprises a condenser hav ing fixed stator plates and av rotor. having. plates carried on a .rotatable shaft.

It is the principal object of my invention, to provide a. radio tuning structure which will. produce very accuratetuning; that is: to say, after any one station has, been set for its maximum effective tuning position, it will repeat on successive operationsof its tunine button.

Another object of my invention is to provide a. structure which may be operated either automatically or ma'r-i-ually and by automatically 1 mean bymerely pushing; in a button. or plunger;

A still further object of: my invention is to provide a structure in which different broadcast stations may be :easily and accurately tuned from the front plate or-dialof the rad-inset, therebein no parts to remove-to get at anyihidden dev-ice for setting any particular button for a given radio station.

Another object of my invention is to provide as part of the automatic means a structure which operates quickly and positively to move the tuning member to one of its. two maximum positions-ofmovement, and then automatically release itself, whereby the tuning element will move underthe influence of a spring back to a positive stop which has been set by merely pushing a button.

Other objects will be clear to one skilled in this art from reading the specification wherein:

Figure l is af-ront view of the structure showing the position of the adjusting, buttons and tuning plungers.

E'igureZ is a plan view of the structure.

(Figure-3 is a side elevational View of the ;structure.

Figure '4 is an end view ofthe structurelooking from left to right of Figure 2.

Figure is a view ontheline 5-5 of Figure. 2, with the moving parts shown in full lines in one position of operation, just before the stop position is reached, and in dotted lines .in another position of operation.

Figure Bis. a view on the line 'G G of Figure 2.

Figure 'Tis aview similar. to Figure 5., but with the movable parts in another position of operation.

Figure 8 isa view ofcertain of themanual control devices in certain positions of operation.

Figure 9 is an enlarged view partly in section and partly elevation approximately 0n the line Figure lois a diagrammatic. view showing the circuits; controlling. the automatic actuation of theistructure.

in the.- various; views, wherein like numbers; are fer to corresponding parts, I is abnacket which may be attached to some, member of the radio cabinet. 0n the bracket 1 is; supported a frame 2. carrying stators 3-, three being illustrated,, and their cooperating rotors '41-. The rotors '4' are carried orra shaft 5 which, extends through theend plates: 6 and The rotor shaft 5 is supported in thenend plates '6 and 1 according tomy Patent 1,800=,f7;1%9;;iSS11ed April 14, 1 931...

At the end of the structure having the end plate 5, which may bereferred toas the. rearend; there isfastened: to the end plate 6 a device generally referred; to. as a solenoid, having a wind ing -8;, fieldelements 9 and a circular type of core tilhaving an arm It fastened, to: the-end 12 of the rotor shaft 5. The construction of: this device need not be further described as reference may be had to my Patent No. 2,337,375, issued December 21, 1943, except to mention that a spring I3; which is fastened at one end to l4, hasits convolutions positioned in a spool 15 and fastened thereto, it. being; understood that. the spool is fastened through its hub Iii-to the end .I 2 of the rotor shaft-5.

Also fastened to this end of the. structure; adjacent the solenoid armature I0, is an electromag'net. l-l positi-oned within the'zfield member i=8. A plunger I19 extends through the-electro-magnet H and provided at one endwith a head 2i] is -adapted toibeengaged by an arm, 21 .iastened to the solenoid! armature ill The lower end of the plunger til-rests onan insulating button 22efixedly carriedin the end of aspring .23 that. is. mounted oncan. insulator .24.. The insulater 2 4: carriesa fixed contact member 25 normally in: engagement with-a doublesended contact 26' carriedby the. spring 23. Also carried by the insulator 24 isa-nother spring 2.! carryinga contact 2 8, These. contacts, as well asfi h electrornagnet, Hi, and the solenoid .8. are connected as illustrated in Figure. 10 to a source of current such as a transformer T, towhich refer" ence willv be later made.

vAt the front end. of the, structure, the front plate, 1 carries a bracket .29. having arms 31B and 31- extending, outwardly and to which .arev fastened, in asuitable manner as. by screws 32, a front plate. 33. Mounted. on the front plate 3'3 area plurality'of buttons! carrying plungers 3.5 the inner ends of which: terminate in discs 36 which have pins 311 fastened thereto near-the peripheral edges of the discs. The pins 31 are provided with heads 38 for a purpose which will be later explained.

The buttons 34 have reduced portions passing through the plate 33 and are provided with annular groove 39 which are somewhat wider than the thickness of the plate 33 to provide for the reception of forked locking members 40. The buttons 34 are provided with stops 4| which are adapted to engage lugs or projections 42 preferably integral with and thrown outwardly from the plate 33. The buttons 34 have rough or knurled surfaces 43 whereby they may be gripped su cient y hard so that the buttons may be turned in the plate 33 to thereby change the location of the pins 37, it being understood that the plungers 35 have a side slabbed off so as to prevent their rotation in the buttons 34. It will be noted, however, that the buttons 34 have cross-slots 44 in their front faces so that if, for any reason, the buttons 34 turn too hard for some person's grip, a screw driver may be used, in which case the plunger 35 is merely pushed inwardly to allow the end of the screw driver to enter the slot 44.

Supported by the plate 33, is a bushing 45 held in position by lock nuts 46 and 41. Also carried by the bushing 45 is a spacing collar 48, and in contact with this spacing collar 48 is a spring member 49 having a plurality of spring-contact fingers 50 which extend into engagement with the discs 36, one for each of the eight discs shown. Also carried by the metallic bushing 45, is another spring member insulated by the insulators 52, 53 and 54 from the sleeve 45. The spring member 5i is, like the spring member 43, divided into the same number of contact fingers 55 having contacts 56 of suitable material to be engaged by their cooperative fingers 58 forming a part of the contact member 49.

Fastened to the rotor shaft 5, adjacent the bushing 45, as by a set screw 51, is a collar 58 to which is fastened an arm 59. On the free end of the arm 59 are fastened a pair of thin metallic blades 68 and 6| made of suitable metal such as steel treated to prevent rusting, or prosphor bronze.

When the parts are in normal position-as indicated in Figure 2, the free ends of the blades 5! and BI are in planes'which are spaced a short distance in front of the heads 38 of the pins 31, so that when one of the plungers 35 is pushed inwardly, the pin 31 will be in the path of return movement of either the blade 68 or Bl as and for the purposes which will be later referred to.

Rotatably mounted on the rotor shaft 5, is a hub 32 to which is fastened a'gear wheel 63. This gear wheel has a single pin 64 having a head similar to the heads 33 on the pins 31. The gear 63 also has stop portions 83 and 84, the purpose of which will be later described. Also fastened to the rotor shaft 5, is a collar 65 to which is fastened an auxiliary blade 66 formed and positioned so that its free end just clears the head of the pin 64 during normal rotation of the rotor shaft 5.

Spaced from the frame 2 by a spacer 61, but fastened to the frame as by a screw 68, is a short, stiff plate 69, the end of which encompasses the rotor shaft 5. Between the plate 69 and the gear wheel 53, is a spring which normally pushes the hub 62 against the outer peripheral edge of a plate Tl that is fastened to a stub shaft 12 carried by a bushing 13 fastened to asupplemental front plate 74 which in turn is fastened to or made integral with the lower part of the main front plate 33.

The inner end of the stub shaft 12 carries an elongated pinion 15 which is in continual mesh with the gear 63. To the outer end of the stub shraft T2 is fastened a push button 16 having a flange l1 adapted to engage the end of a pin I8 supported by a bushing 19 fastened to the supplemental plate 14. The inner end of the pin 18, which may be of metal, is in contact with or at least closely adjacent to a contact finger 88 which forms a part of the contact member 49. Adjacent the spring contact member 88, is a cooperating spring finger 8| which forms a part of the spring member 5!. The spring 8| has a contact 82 adapted to be engaged by the spring 8!) when the button 15 i pushed inwardly for a purpose which will be presently described.

Coming now to the operation of the structure,- assuming that it is desired to operate the same manually, the push button 16 is pushed inwardly which causes the spring 83 to engage the contact 82, allowing current to pass from the secondary of the transformer T to the solenoid 8, contact 25, and contact 25 on the spring 23, and to the spring 5|, finger 8|, contact 82 and spring 80, to the ground side of the secondary of the transformer, thereby completing a circuit through the solenoid, causing it to operate, which it does very quickly, to the full limit of its stroke, whereby the arm 2| engages or hits the head 20 of the plunger l9, causing it to open the contacts 25 and 26, and to close the contacts 26 and 28 through the electro-magnet I1, and back through the contacts 82 and 80. This opens the circuit through the solenoid 8 and allows the spring l3 to start the rotor shaft on its return movement.

When the button 16 is pushed inwardly, the circular plate H, which is in engagement with the hub 82, pushes the hub, with the gear 63, to the left, looking at Figure 3, against'the tension of the spring 10, and moves the pin 64 into the path of the return movementof the spring 66, so that after the solenoid armature has been released and the rotor shaft, with the rotor plates, starts on its return movement, this movement is stopped by the blade 65 engaging the pin 64 wherever it may be positioned, as illustrated in Figure 8. After this happens, pressure is removed from the button 15, and the spring 10 then moves the gear 63 and associated parts back to normal position, opening the contacts 88-82 at the same time the spring 66 is held on the pin 64 by the head thereof. The rotor shaft may then be turned in either direction by rotating the push button 15 until the stop portions 83 and 84 on the gear 53 come into contact with the pinion F5. The stops 83 and 84 are so positioned on the gear 63 as to allow the rotor shaft to be turned from an all-in or full-capacity position to an all-out or zero-capacity position. The circular plate II, in addition to acting as a lateral transfer agent for the gear 63, also acts as a brake against the hub 62, thereby holding the rotor in any adjusted position against the tension of the spring I3.

The structure may be converted back to What I have termed an automatic control by the mere pushing inwardly of one of the plungers 35 which, from FigurelO, it will be seen energizes the solenoid 8, causing the armature H] to move to its full-stroke as heretofore explained, at which time the manual blade 66 is moved to the position shown in dotted lines in Figure 5, away from the headed pin 64, allowing the blade 66 to return to shearer its. normal lateral position, and the bladeslac-ea are-stopped according. to the button 35 that has been pushed asrwill now be explained.

In: the: automaticoperation of the structure, it is only necessary to push inwardly any one of the plungers '35 which closes a contact between one of the fingers of the contact member 49 and the contact 55 carried by a'finger 55, and this completes a circuit through the solenoid 8- which is actuated in the manner heretofore described, moving the rotor to one of its two fully operated vpositions, that shown being the zero capadity position, in which position the blades fibandti willbe as shown in Figure 6.

When: the armature Hl, through its arm '21, engages-the head 26 of the plunger Id of the electro-magnet- 11, the solenoid will be deenergized and the spring t3 will start the armature, with the rotor shaft and rotors, on its return movement; but since the plunger 35 is pushed to its inward position, one of the pins 31 will be engaged by either one of the blades til or t'l, depending on. which plunger is pushed, and this will stop themovement of the rotor in the tuning position as defined by the location of the pin 31. The free ends of the blades 60 and 6! may engage the pin 31 at some point between its head 3'8 and the discs 35, butwhen the plunger 3'5 is released, allowing it to return to normal position pressure of the spring finger Ell, the head .38 prevents the flexible blade from moving off the pin as the blade is flexed laterally toward the front plate 3-3, thereby stopping the plunger in the position governed by the location of the pin.

Gm-actuation of another plunger, the solenoid 8 i'sactuated', which moves the setting blades 60 and fi l tothe position-shown in Figure 6-as heretoiore. described. This releases the previous engagement-and allows the blades 60 and l, whichever one has been engaged, to return to normal lateral position.

As has-been heretofore explained, the rotation of any-ofthebuttons 43 will shift the location of their pins over a certain arc. While the drawings show eight buttons with adjustments thereof as described sufiicient to give tuning abil ity over the entire broadcast range, either a greater or smaller number of buttons may be used: While I- have shown the apparatus in connection with atuning condenser, the device may be applied to any rotatable tuning member and also toany oscillating tuning member where the oscillation is accomplished by a cam, crankshaft or cable, through the rotatable movement of a shaft. Furthermore, while I have shown a transformer T forsupplying the current for the solenoid 8' andelectro-magnet H, it is to be understood that'these devices may be wound to operate from a standard llO-bolt lighting circuit, either A. C. or D'. C.

'Itwlll be obvious that certain of the details may be varied without departing from the spirit of my invention or the scope of the appended claims.

What I' claim is:

I. A radio tuning structure including a rotatable tuning member having two maximum positions of movement, means includin an electromagnetpositioned in. a circuit normally open at cooperative contacts for moving said member to one of its two maximum positions of movement, means for then automatically moving the tuning member toward the other maximum position-,and means for stopping the tuning member on its return movement at a predetermined tuning position, said stopping means including: a pair of: spaced flexible bladesmounted to rotate with the tuning member, a plate positioned laterallyfrom said blades, a plurality of buttons carried by the plate and each carrying'a plunger extending through the plate, a disc on this extended end of each plunger, each disc having av in with a head thereon to stop and retain one or said flexible blades when its cooperative plunger is pushed longitudinally inwardly, and a springboatact member having fingers positioned over the path of longitudinal movement of the discs and moved into engagement with another of said cooperative contacts to close said normally open circuit for actuating said electro-magnet.

2. A radio tuning structure including a rotatable tuning member having two maximum positions of movement, means including an electromagnet positioned in a circuit normallyopen at cooperative contacts for moving said member to one of its two maximum positions of movement, means for then automatically moving, the tuning member toward the other maximum position, and means for stopping the tuning member on its return movement at a predetermined tuning position, said stopping means including a pair of spaced flexible blades mounted to rotate with the tuning member, a plate positioned laterally from said blades, a plurality of buttons rotatably carried by the plate, with means on the plate for fixing the amount of rotation of the buttons, each button carrying aplunger extending through the plate, a disc on this extended end of each plunger, each disc having a pinwith a head thereon to stop and retain one of said flexible blades when its cooperative plunger'is pushed longitudinally inwardly, and a spring contact member having fingers positioned over the path of iongi tudinal movement of the discs and moved into engagement with another ofsaid cooperative contacts to close said normally open circuit for actuating said electro-magnet.

3. A radio tuning structure including a rotatable tuning member having two maximum position of movement, means including an electromagnet positioned in a circuit normally open at cooperative contacts for moving said member to one of its two maximum positions of. movement, means for then automatically moving the tuning member toward the other maximum position, and means for stopping the tuning member on its return movement at a predetermined tuning posi tion, said stopping means including a pair of spaced flexible blades mounted to rotate with the tuning member, a plate positioned laterally from said blades, a plurality of buttons rotatably carried by th plate, with means on the plate for fixing the amount of rotation of the buttons, each button carrying a plunger slidable but non-rotatable in the button, the plungers extending through the plate and each having a disc on its extending end, each disc having a pin with a head thereon to stop and retain one of said flexible blades when its cooperative plunger is pushed longitudinally inwardly, and a spring contact member having fingers positioned ove the path of longitudinal movement of the discs and moved into engagement with another of said cooperative contacts to close said normally open circuit for actuating said electro-magnet.

4. A radio tuning structure as defined. in claim 1, further "characterized in that. there are eight buttons, each with its selective stop plunger, the plungers being non-rotatably carried by their respective buttons, the buttons being rotatably adjustable in the plate whereby the pins on said disc may be positioned through an arc to vary the position at which said flexible blades are engaged and stopped so the number of said buttons may cover the normal broadcast tuning range.

5. A radio tuning structure as defined in claim 1, further characterized in that each of said buttons has means for assisting in turning it, and a reduced end passing through the plate, and an annular groove adjacent said reduced end with a forked spring member positioned in said groove and engaging the plate beyond the diameter of said reduced end to adjustably hold the button to the plate.

6. A radio tuning structure as defined in claim 1, further characterized in that the spring contact fingers continuously press against their respective discs to hold the plungers in neutral position and also to return any plunger to neutral position after it has been released from one of said operations.

7. A radio tuning structure as defined in claim 1, further characterized in that the said disc pins are long enough to allow the ends of said blades which engage the pins to slip thereon into engagement with the pin heads, while the blades are flexible enough to easily slip by the head of a pin if the same is pushed inwardly far enough by its plunger to be engaged by a blade on moving to one of said maximum positions, and also to allow the spring fingers to move their discs toward the plate at least sufiiciently to allow the fingers to open the said circuit when pressure is removed from the operated plunger.

, 8. A radio tuning structure as defined in claim 1, further characterized in that the plungers are non-rotatably carried by the buttons which are rotatably adjustable n the plate through a fixed range, the pins being fastened to the discs near 7 their peripheral edges whereby adjustment of the buttons changes the arcuate position of stoppage of the blades, and hence the final position of the tuning member. r

9. A radio tuning structure as defined in claim 1, further characterized in that the flexible blades are carried on an arm fastened to rotate with an element of the tuning member, the free ends of said blades being normally in a plane just adjacent the heads of said pins when they are in idle position, whereby when the discs and pins are moved inwardly sufficiently toclose said circuit, any one pin that is operated by its plunger will be engaged by the ends of one of said blades to :top the tuning member in a desired tuning posi- 10. A radio tuning structure as defined in claim 1, further characterized in that said first-mentioned means includes a solenoid having a circular type armature having an arcuate movement of at least 180 degrees and directly connected to the rotatable tuning member, the solenoid being energized by one of said plungers, moving by its disc, one of said spring fingers -to close a circuit through the solenoid.

11. A radio tuning structure as defined in claim 1, further characterized in that said first-mentioned means includes a solenoid having a circular type armature having an arcuate movement of at least 180 degrees and directly connected to the rotatable tuning member, the solenoid being energized by one of said plungers, moving by its disc,.one of said spring fingers to close a circuit through the solenoid, said secondmentioned means including a. return spring au-.

tomatically brought into action by the solenoid armature on completion of its initial movement.

12. A radio tuning structure as defined in claim 1, further characterized in that said first-mentioned means includes a solenoid having a circular type armature having an arcuate movement of at least degrees and directly connected to the rotatable tuning member, the solenoid being energized by one of said plungers, moving by its disc, one of said spring fingers to close a circuit through the solenoid, said second-mentioned means including a return spring automatically brought into action by the solenoid armature operating the plunger of an electro-magnet, this plunger opening the said solenoid circuit, allowing the return spring to act, and at the same time establishing a circuit through the electro-magnet and the push-button contact finger which energizes the solenoid as and for the purpose described.

13. A radio tuning structure including a rotatable tuning member having two maximum positions of movement, means for moving said member to one of its two maximum positions of movement, means for then automatically moving the tuning member toward the other maximum position, and means for stopping the tuning member on its return movement so as to secure manual control of the tuning member, said stopping means including, a manually operable push button fastened to a stub shaft supported in a bushing, a support for the bushing, a pinion and a circular plate on the inner end of the stub shaft, a gear slidably and rotatably mounted on, but independent of an element of the tuning member and in mesh with said pinion, the gear having a hub normally in engagement with the edge of said circular plate, a headed pin projecting from the gear, a flexible blade mounted to rotate with the said element of the tuning member and having its free end positioned so as to travel in a plane closely adjacent the head of said pin when both are in inoperative position, a spring acting against the gear for normally holding the gear so the pin is not engaged by the blade when manual control is not desired, but when the said push button is moved inwardly, the pin is engaged by said blade when the tuning member moves from one maximum position of movement toward the other maximum position, and a pair of contacts closed by the push button when it is moved to slide said gear, said pair of contacts acting to close a circuit through said first-mentioned means to allow said second-mentioned means to bring said blade back against said gear pin, whereby the tuning member may then be moved by turning said push button.

14. A radio tuning structure including at least one stator and rotor carried in a frame with the rotor shaft extending through both ends of the frame, a solenoid and an electro-magnet fastened to one end of the frame, the solenoid having an arcuately formed armature fastened to the rotor shaft and being capable of turning through at least 180 degrees, and a spring for returning the armature after it reaches the end of its working stroke, the electro-magnet having a core movable lcngitudinally of its length to open and close a pair of contacts which control a circuit through the solenoid, the solenoid armature having means for engaging and moving, at the end of its stroke, the said core to cause it to move said contacts; a bracket fastened to the opposite end of the frame, a plate carried by the bracket, a plurality of rotatably adjustable buttons arcuately carried on the front of the plate, each button having a push-plunger, and each plunger having a disc positioned just adjacent the inner surface of the plate, each disc having a pin extending therefrom and terminating in a head, a pair of contact members carried by the plate adjacent its inner face, one of said contact members having fingers engaging said discs as and for the purpose described, while the other contact member is at least insulated from the plate and frame, and is electrically connected to one of said pairs of contacts controlled by said elect-ro-magnet, and has fingers to cooperate with the firstmentioned fingers to close a circuit through the least one stator and rotor carried in a frame, with the rotor shaft extending through both ends of the frame, a solenoid positioned at one end of the frame and having an armature fastened to the rotor shaft and being capable of directly turning the rotor shaft through a full movement in one direction, and a spring for returning the armature and rotor after said movement is completed, an electro-magnet having a pair of closed contacts and a pair of open contacts, and also having an energizable part adapted to be mechanically engaged by the solenoid armature at the end of its Workin stroke to open the closed contacts and close the open contacts, a bracket fastened to the opposit end of the frame, a face plate fastened to the bracket, a plurality of rotatably adjustable supports mounted on the plate and having push-plungers extending through the supports, each plunger having a disc on its inner end and each disc having a headed pin, a pair of contact members, one insulated from the other, carried by the plate and each having contact fingers, one pair for each disc, with one of the fingers of the pair in pressing engagement with its disc, while the other insulated finger of the pair is electrically connected through said closed contacts of the electro-magnet to the solenoid, whereby when a push-plunger is operated to connect its pair of fingers, the solenoid is energized and then deenergized as andfor the purposes described, and a pair of flexible blades fastened to rotate with the rotor and adapted to engage one of said pins on the return movement of the rotor when the pin and its disc are pushed inwardly by their plunger, a stub shaft carried by the plate and having an individual push-button, an elongated pinion and circular push-and-brake plate fastened to the stub shaft, a gear slidably and rotatably mounted on but independent of the rotor shaft and in mesh with the pinion, the gear having a hub engaging the push-and-brake plate, a headed pin projecting from the gear, a flexible blade mounted to rotate with the rotor and having its free end adapted to engage the gear pin and to be held thereby by means of the head on the pin when the gear is moved sufficiently toward the blade by the push button, a pair of contacts adapted to be closed by the push button when it is moved to slide the gear, said pair of contacts acting through the closed contacts of the electro-magnet to energize the solenoid as described, and a spring acting against the gear for reutrning it to normal lateral .position after it has been released from the inward pressure on the push button.

16. A radio tuning structure including a rotatable tuning member having two maximum positions of movement, means including an electromagnet in a normally open circuit for moving said member to one of its two maximum positions of movement, means for then automatically moving the tuning member toward the other maximum position, and means for stopping the tuning memher on its return movement at a predetermined tuning position, said stopping means including at least one flexible blade mounted to rotate with the tuning member, a plurality of push members arcuately mounted so a part carried by any one may be moved into the path of travel of said blade to stop it and the tuning member on its return movement, and cooperative electrical contacts brought into engagement by the push member when it is initially moved to close said normally open circuit for actuating said electro-magnet.

17. A radio tuning structure as defined in claim 16, further characterized in that the mountings for the push members are rotatably adjustable whereby the tuning range of each push member may be extended over a predetermined range.

18. A radio tuning structure including a rotatable tuning member having two maximum positions of movement, means including an electromagnet in a normally open circuit for moving said member to one of its two maximum positions of movement, means for then automatically moving the tuning member toward the other maximum position, and means for stopping the tuning member on its return movement at a predetermined tuning position, said stopping means including a pair of flexible blades mounted in spaced radia1 relation to rotate with the tuning member, a plurality of adjustable buttons mounted in spaced arcuat and radial relation, each button non-rotatably carrying a push-plunger, on the inner end of which is carried a headed pin which acts to engage one of said blades on its return movement and stop the tuning member in 

